[Bronchoalveolar lavage].

The incidence of interstitial lung diseases is increased during the last years. A possibility for improvement the diagnosis of these lung diseases is the bronchoalveolar lavage (BAL). In a critical review the performance of the BAL, same properties of the isolated macrophages and the determination of biochemical parameters in lavage fluid are described. In this context especially problems of diagnosis of sarcoidosis are discussed. There are new fields of application of BAL (diagnosis of occupational lung diseases, control of therapy). In order to improve the comparability of different results a standardization of BAL is necessary.